简介:TheHAZmicrostructureandperformanceofQuenchingandTemperingmodetemperbeadweldingandgeneralweldedjointswhichweremadeonSA508-3steelof60mmthicknesswerecomparedinthisarticle.Theresultshowsthattemperingsorbitewhichhasexcellentoverallperformancewasobtainedinbothmodes.ThemicrostructureofQuenchingandTemperingmodeweldedjointsgotmorefinegrain.Eventhoughthehardnessoftemperingbeadweldedjointsishigherthanthegeneralone,itstillmeetsthestandardswhichislowerthan350HV.TheimpactabsorbingenergyofeachdistrictoftemperingbeadweldedjointsHAZreached170J,whichisequaltogeneralone.
简介:Fe(OH)3precursorsolwaspreparedbyasol-gelmethod.Theprecursorsolwasdippedontotheabsorbentcotton,andgelwasformedontheabsorbentcottontemplateafterthevolatilizationofmoisture.Fe2O3microtubulesweresynthesizedaftertheprocessofself-propagationorcalcination.Thephase,morphology,andparticlediameterofthesampleswereexaminedbyX-raydiffraction(XRD)andscanningelectronmicroscopy(SEM),andthemagneticpropertiesofthesamplesweremeasuredusingavibratingsamplemagnetometer(VSM).TheexternaldiametersofFe2O3microtubulesrangedbetween8and13μm,andthewallthicknessesrangedbetween0.5and2μm.ThetypeofthecalcinationmethodplaysasignificantroleindevelopingtheFe2O3phaseandthevariationinthemagneticpropertiesinthesol-geltemplatecomplexingmethod.γ-Fe2O3wassynthesizedbyaself-propagationmethod.However,α-Fe2O3wassynthesizedaftercalcinationat400°Cfor2h.Thecoercivityofthesamplessynthesizedbycalcinationat400°Cfor2hafterself-propagationwasfoundtoincreasesignificantly,therebypresentinghardmagneticproperties.
简介:采用化学平衡模拟软件GEMS预测了锌湿法冶金过程中涉及的锌在Zn(Ⅱ)-NH3-H2O和Zn(Ⅱ)-NH3-Cl--H2O体系中的溶解度,并构建了其含锌物种分布图和优势区图。采用平衡实验方法测定了相同条件下锌的溶解度,其结果与预测结果相吻合。含锌物种的分布图和优势区图表明,在弱碱性条件下,2个体系均为以锌氨和羟基锌氨配合物为溶液的主要物种,其中Zn(NH3)24-为主要优势物种;在Zn(Ⅱ)-NH3-Cl--H2O体系中,锌氨氯三元配合物的形成能有效增大锌在中性条件下的溶解度,在该体系中存在Zn(OH)2、Zn(OH)1.6Cl0.4和Zn(NH3)2Cl23种固相,固相产物的形成取决于体系中总锌、总氨和总氯浓度。这些热力学平衡图表明了体系中各种物种之间的相互影响作用,并预测了总氨和总氯浓度的变化对锌溶解度的影响,为锌湿法冶金提供了热力学数据。
简介:Pt(Ⅱ)andPd(Ⅱ)complexeswith2',3',4',5,7-pentahydroxy-flavoneweresynthesizedandcharacterizedbyelementalanalysis,molarconductance,IR,1HNMR,TG-DTA,UV-Visspectroscopictechniques,andfluorescenceanalysis.Thescavengingeffectonthesuperoxideradical(O-2)andtheinhibitoryeffectonlipidperoxideswerealsoinvestigated.Boththeligandandthecomplexesexhibitscavengingeffectonsuperoxideradicals,andtheeffectofthecomplexesisgreaterthanthatoftheligand.ThePt(Ⅱ)complexexhibitsthestrongestscavengingefficiency.BothPt(Ⅱ)andPd(Ⅱ)complexeshavetheinhibitoryeffectonlipidperoxides,andtheeffectofthecomplexesisgreaterthanthatoftheligand,butthePt(Ⅱ)complexhasahigheffectofpromotinglipidperoxides.
简介:Fe3AlandCr18-Ni8steelwerebondedinvacuumandaninterfacewasformedbetweenFe3AlandCr18-Ni8steel.Stressdistributionatthediffusion-bondedinterfacewasresearchedbynumericalsimulationandfiniteelementmethod(FEM).TheresultsindicatedthatthepeakstressappearedattheinterfacenearCr18-Ni8steelside.Thisisthekeyfactortoinducecrackatthisposition.Withtheenhancementofheatingtemperature,thepeakstressatthebondedinterfaceincreases.Whenthetemperatureis1100℃,thepeakstressisupto65.9MPa,whichisbiggerthanthatat1000℃by9.4%.Inaddition,thepeakstressbecomesbiggerwiththeincreaseofthethicknessofbasemetalfrom1mmto8mm.Whilethethicknessismorethan8mm,thepeakstressvariesslightlywiththechangeofthethickness.
简介:Mg–9Li–3Al–1.6Yalloyswerepreparedthroughmixturemethod.Themicrostructure,mechanicalproperties,andcorrosionresistanceoftheas-castandasextrudedalloyswerestudiedbyopticalmicroscopy(OM),scanningelectronicmicroscopy(SEM),X-raydiffraction(XRD),mechanicalpropertiestesting,andelectrochemicalmeasurement.Theas-castMg–9Li–3Al–1.6Yalloywiththeaveragegrainsizeof325lmiscomposedofb-Limatrix,blocka-Mg,andgranuleAl2Yphases.Afterextrusion,thegrainsizeoftheas-castalloyisobviouslyrefinedandreachesto75lm;thestrengthandelongationoftheextrudedalloyareenhancedby17.20%and49.45%,respectively,owingtotheirfinemicrostructureandreductionofcastingdefects.Theas-extrudedalloyshowsbettercorrosionresistancecomparedtotheas-castone,whichmayberelatedtothelowstoredenergyanddislocationdensityintheextrudedalloy,alsothehomogenizationtreatmentbeforeextrusion.
简介:通过一个简单的水热方法成功地合成出由SnO2纳米片作次级结构的新型花状ZnSnO3-SnO2分级纳米结构。ZnSnO3多面体在生长分级SnO2纳米片的过程中主要起模版作用,制备出的SnO2纳米片的厚度约为25nm。还讨论了ZnSnO3-SnO2样品的形貌随反应时间变化的规律,并且进一步讨论了形成这种分级结构的形成机制。此外,由这种新型ZnSnO3-SnO2纳米结构作敏感材料的气体传感器对乙醇气体具有高灵敏和快响应的特点。ZnSnO3-SnO2纳米片在最佳工作温度270°C时,对50×10-6乙醇气体的灵敏度约为27.8,其响应和恢复时间分别在1s和1.8s内。
简介:ThemicrostructuresandcrystallizationbehaviorofTi–47at%Ni–3at%Feshapememoryalloywireundertheconditionofseverecolddrawingatroomtemperatureanddifferentpost-deformationannealingprocesseswereintensivelyinvestigatedusingtransmissionelectronmicroscope(TEM)anddifferentialscanningcalorimetry(DSC).ItisindicatedthattheamorphousphaseisdominantintheTi50Ni47Fe3wireafterthecolddrawingof78%arealreduction.Thecriticaltemperatureforrecrystalizationisdeterminedatabout300°C.Theaveragegrainsizegrowsfrom7upto125nmwhenannealingtemperaturerisesfrom300to500°C.Post-deformationannealingprocessexertssignificantinfluenceonthecrystallizationtemperaturewhichclimbsupwiththeincreaseofannealingtemperature.
简介:Au/-Al2O3催化剂被免职降水方法为低集中白酒溪流(甲醇,乙醇,iso-propanol和n-propanol)的催化燃烧作好准备。催化剂被X光检查光电子描绘光谱学(XPS),X光检查diffractometry(XRD)和精力散X光检查微分析(版本)技术。XPS结果证明仅仅催化剂的表面上有Au0。XRD模式证明Au高度大概在-Al2O3上被驱散。为有2.0g/m3的集中的甲醇,乙醇,iso-propanol和n-propanol的完全的变换的温度是60,155,170和137?,分别地但是他们完全在60,220,260和217点被使矿物化进CO2和H2O吗?分别地在优化催化剂上。催化剂的活动在130h是稳定的。为催化甲醇消除的动力学跟随了伪--首先订表示为r=0.6528c0+0.084的反应2。明显的激活精力的价值是在反应温度的范围的54.7kJ/mol。
简介:ThedistributionsoftheaxialstressandshearstressinAl2O3-TiC/Q235diffusionbondedjointswerestudiedusingfiniteelementmethod(FEM).Theeffectofinterlayerthicknessontheaxialstressandshearstresswasalsoinvestigated.Theresultsindicatethatthegradientsoftheaxialstressandshearstressaregreatnearthejointedge.ThemaximalshearstressproducesattheinterfaceoftheAl2O3-TiCandTiinterlayer.WiththeincreaseofCuinterlayerthickness,themagnitudesoftheaxialstressandshearstressfirstdecreaseandthenincrease.Thedistributionoftheaxialstresschangesgreatlywithalittlechangeintheshearstress.TheshearfractureinitiatesattheinterfaceoftheAl2O3-TiC/TiinterlayerwithhighshearstressandthenpropagatestotheAl2O3-TiCside,whichisconsistentwiththestressFEMcalculatingresults.